MR Arthrography of the Hip: Diagnostic Performance and Image Quality of 3D Steady-State Free Precession versus 2D Turbo Spin-Echo Sequences

Introduction: To compare the diagnostic performance and image quality of an isotropic three-dimensional (3D) steady-state free precession (SSFP) sequence with the current diagnostic standard two-dimensional (2D) proton-density (PD)-weighted turbo spin-echo (TSE) protocol in hip magnetic resonance arthrography (MRA) with arthroscopy as a standard of reference.

Materials and Methods: A total of 81 patients (age: 39.5 ± 11.1 years) with hip pain and suspected labral tears were included and underwent hip MRA with intra-articular contrast media on a 3-T scanner. Two-dimensional PD-weighted TSE was acquired in the axial, coronal, and sagittal planes (total acquisition time: 10 minutes) in keeping with the current diagnostic standard and a parasagittal 3D SSFP sequence (total acquisition time: 5.34 minutes). MRI data were reviewed independently regarding labral tears, cartilage pathology, and bone marrow edema by two blinded experienced musculoskeletal radiologists. Lesion detection and image quality were assessed using a 5-point Likert scale. In 39 patients, diagnostic accuracy of the two assessed sequences could be determined using invasive arthroscopy as the gold standard.

Results: Based on image quality, diagnostic confidence when evaluating the labrum and cartilage was rated higher by both readers for the 3D SSFP (4.5 ± 0.8; 4.35 ± 0.7; p < 0.0001) compared with the 2D TSE-PD sequence. In the subset of patients with invasive arthroscopy, a similar sensitivity (81.3% and 90.6%) but higher specificity (74.4% for both) in the evaluation of labral tears and cartilage alterations was found for the 3D SSFP sequence versus the 2D TSE-PD sequences (sensitivity: 84.4 and 87.5%; specificity: 42.9%). For bone marrow evaluation, both readers rated diagnostic confidence based on image quality of the 2D TSE-PD sequence higher compared with the 3D SSFP sequence (p < 0.0001).

Conclusion: In MR hip arthrography, a 3D SSFP sequence offers increased accuracy in the detection of labral tears and cartilage alterations compared with the current diagnostic standard 2D TSE-PD sequences. At the same time it also offers a higher time efficiency of MRI. A major drawback of 3D SSFP compared with 2D TSE-PD was the inferior diagnostic confidence for the evaluation of bone marrow. Thus 3D SSFP should still be combined with conventional 2D TSE sequences.